A dry etching device, which is a processing device for a semiconductor wafer, forces ionized gas molecules to act on a wafer surface through an electric field between parallel plate condensers in a gas chamber. However, a wafer fixing jig is damaged with time in such processing, which disturbs the electric field on an outer periphery of the wafer and disables perpendicular processing to the wafer. In a hole having a high aspect ratio which is processed on a DRAM (Dynamic Random Access Memory) or a 3D-NAND (3-Dimension NAND type flush memory), the hole is inclined, which causes a decrease in yield.
PTL 1 discloses a method, for the purpose of inspecting a hole pattern formed on a substrate, of obtaining an image of the hole pattern, obtaining an upper surface shape and a lower surface shape of the hole pattern from the image, and detecting a positional displacement between the upper surface and the lower surface of the hole pattern. FIG. 2 of PTL 1 shows that such displacement is caused by inclination of the hole.
PTL 2 discloses an electron beam microscope system for measuring a hole pattern on a substrate, which is capable of obtaining respective images of backscattered electrons and secondary electrons, detecting a top contour of a hole from the secondary electron image and a bottom contour of the hole from the backscattered electron image, and determining that the hole is not provided perpendicularly by evaluating displacement of centers of each of the contours.
PTL 3 discloses an electron beam microscope system for measuring an overlay of a hole pattern on a substrate, and discloses a method of dividing and recognizing circuit pattern regions formed in each process, quantifying a difference between a reference image and a measured image through image processing with respect to each of the patterns, and calculating an overlay from a result of quantification of the difference.
PTL 4 discloses an electron beam microscope system for measuring a hole pattern on a substrate, and discloses a method of providing a means for irradiating a sample with a primary electron beam accelerated by a high acceleration voltage and a means for detecting backward scattered electrons of low angles, and measuring a depth of a hole and a diameter of a hole bottom by detecting electrons emitted from the hole bottom passing through the sample.